Golang program to write into a file

In go programming language we can use os.create and ioutil.WriteFile to write into a file. In Go, the OS can be used to represent a file. os package file type that offers ways to open, read from, write to, and manipulate files.

Method 1: Using os.Create function

We make use of the os.Create in this program to start a new file or, if one already exists, to open it. The file is deferred while a string is written using the WriteString function. Close makes ensuring that when the application ends, the file is correctly closed.

Syntax

Os.Create 

In Go programming language, create is a part of os package , this function creates a new file, it contains a single parameter i.e. the filename which is to be created.

Algorithm

• Step 1 − Create a package main and declare fmt(format package) and os package in the program where main produces executable codes and fmt helps in formatting input and output.

• Step 2 − Use the os.Create in the main to open the file for writing.

• Step 3 − Check for any potential file-creation issues, such as the file not being located.

• Step 4 − After all activities are finished, use the defer keyword to terminate the file.

• Step 5 − Employ the file to write a string to a file, use the WriteString method.

• Step 6 − Verify your text for any mistakes that might appear, such as insufficient permissions.

Example

In this example we will use os.Create function to write into a file. Let’s see how the code is executed.

package main
import (
   "fmt"
   "os"
)
//create main function to execute the program
func main() {
   // Open the file for writing
   file, errs := os.Create("myfile.txt")
   if errs != nil {
      fmt.Println("Failed to create file:", errs)
      return
   }
   defer file.Close()

   // Write the string "Hello, World!" to the file
   _, errs = file.WriteString("Hello, World!")
   if errs != nil {
      fmt.Println("Failed to write to file:", errs) //print the failed message
      return
   }
   fmt.Println("Wrote to file 'myfile.txt'.") //print the success message
}

Output

Wrote to file 'myfile.txt'.

Method 2: Using ioutil.WriteFile

In this program we write a string to a file using the ioutil.WriteFile function. The file name is the first argument, the data to be written as a byte slice is the second argument, and the file permission is the third argument. If something goes wrong, the function returns an error, which we check for throughout the program.

Syntax

ioutil.WriteFile

In Go, WriteFile belongs to ioutil package and contains three parameters, the first is the filename where data is to be written, second is the data which is to be written and third is the file permission. The data is written to the file if function is executed successfully.

Algorithm

• Step 1 − Create a package main and declare fmt(format package) and io/ioutil package in the program where main produces executable codes and fmt helps in formatting input and output.

• Step 2 − Use the ioutil.WriteFile in the main function to write a string to a file.

• Step 3 − The file's name is the first argument and the data that will be written as a byte slice is the second argument. Here, the third argument is the file permission.

• Step 4 − Verify your text for any mistakes that might appear, such as insufficient permissions.

• Step 5 − Print a message stating that the file was successfully written to if there were no issues.

• Step 6 − The print statement is executed using fmt.Println() function

Example

In this example, we will use ioutil.WriteFile method to write into a file. Let’s see via code how it can be executed.

package main
import (
   "fmt"
   "io/ioutil"
)

//create main function to execute the program
func main() {
   // Write the string to the file
   err := ioutil.WriteFile("myfile.txt", []byte("Hello, alexa!"), 0644)
   if err != nil {
      fmt.Println("Failed to write to file:", err)  //print the failed message
      return
   }
   fmt.Println("Wrote to the file 'myfile.txt'.")  //print the success message
}

Output

Wrote to the file 'myfile.txt'.

Conclusion

We executed the program of writing into a file using two methods. In the first method we used os.Create function and in the second example we used ioutil.WriteFile command to execute the program. If the content is written to the file success message is printed but if it cannot write to file , failed message will be printed on the console.